The invention is concerned with improvements in or relating to optical instruments and particularly to the provision of illumination therefor.
In conventional optical instruments, such as for example optical microscopes, the illumination is provided by a lamp using for example a tungsten filament bulb or other similar source having a spreading pattern of light emission. Although means are available to direct the path of the emitted light, e.g. reflective surfaces, condenser lenses and the like, only a portion of the available light is actually used to give the required illumination to the object to be viewed by the optical apparatus.
Moreover, most light sources generate heat and steps must be taken to dissipate the excess heat, by for example the use of cooling vanes, to avoid damage not only to the instrument but also to the object being viewed.
As a result of this, it is usual for the light source for an optical apparatus arrangement to be a disproportionately large part of the whole arrangement, requiring the instrument to be much more bulky than the optical system itself requires, and to involve the use of a sizable voltage supply and current consumption, yet giving a much lower performance than may be required.
One solution which has been offered to the problem of bulk and dissipation of heat from a source close to the optical viewing region has been to lead light from a conventional source to the viewing region through an optical fibre system, but this does not avoid the problem altogether, merely distancing it slightly. In doing so, the efficiency of light utilisation is not improved.
It is an object of the present invention to minimise the above outlined disadvantages.